Active customers play a critical role in the successful implementation of support schemes, paving the way for the emergence of an energy community. This analysis explores the cooperation among active customers and the implications for developing energy communities. Furthermore, the motivations for consumers becoming active customers in the context of Latvia are illuminated, while also exploring the broader context of navigating the complex regulatory landscape to promote self-consumption. In contrast to prior studies, which often focus on individual or homogenous group participation, this analysis uniquely examines collaborative frameworks that incorporate varied customer categories and profiles. This approach not only underscores the role of tailored regulatory structures in fostering self-consumption, but also presents practical policy insights for incentivizing community-based energy models. The findings reveal that individual participation of active customers in support schemes only achieves the minimal self-consumption threshold in 47% of cases. In contrast, membership in an energy community significantly increases this rate, reaching 84%. These encouraging results underscore the importance of promoting energy community membership among active customers, which subsequently demonstrates substantial potential when promoted across diverse load profile categories. Additionally, the integration of photovoltaic and wind turbine technologies consistently improves self-consumption values.

Considering the changes of gas transmission system (hereinafter – GTS) brought about by diversification of gas suppliers, new interconnections with European GTS and implementation of an open electricity market and then an open gas market, a steady-state GTS modelling tool has been developed for future implementation in the risk and resilience analysis and potentially operational planning for different GTS or other purposes. The developed method combines the linearized hydraulic conductivity approach with a technique, derived from a linear electrical circuit analysis and an additional pressure change term for modelling of active non-pipeline elements of GTS. This method also takes into consideration operational limits of compressors and pressure regulators and changes in compressibility factor and gas viscosity based on the gas composition, temperature and pressure. The paper includes part of the results obtained from a validation case study performed for the presented method.

Considering the ambitious climate goals defined by the European Union, the significant share of energy demand represented by buildings, the slow process of their renovation due to challenges such as a need for majority consent from residents and limited available space in dense urban areas, this study aims to foster retrofitting of energy supply systems of multi-storey apartment buildings, improving their sustainability. This entails making the transition to sustainable energy systems more socially acceptable and practical in urban contexts by proposition and demonstration of the potential of a power and heat supply system retrofit that minimises disruptions felt by residents. It integrates rooftop renewable power sources, heat storage with an electric heater, heat pumps, and existing connections to public utility networks. Furthermore, simulation results of both single- and multi-objective optimisation (performed by the genetic algorithm) for equipment selection, as well as conventional and smart control (implemented as a gradient-based optimisation) for daily scheduling, are compared, defining the main scientific contribution of the study. It is found possible to achieve a net present value of up to almost twice the annual energy expenses of the unrenovated building or self-sufficiency rate of up to 41.6% while using conventional control. These benefits can reach 2.6 times or 49.8% if the smart control is applied, demonstrating both the profitability and improved self-sufficiency achievable with the proposed approach in Latvian conditions.

The influence of high-voltage transmission lines on cables with a conductive shield has not been widely studied, especially during transients. In this paper, a lumped parameter model of a transmission line is developed in the Laplace domain in addition to a steady-state model to determine the effect of a free decaying component of a current induced into a fiber-optic cable shield. Numerical inverse Laplace transform and linear circuit theory is combined in a solution applicable to models containing mutual induction and electrostatic links between different conductors. A case study is performed for a steel-shielded fiber-optic cable installed on a 110 kV line, which indicates that the induced current is a significant threat to the cable considered. The demonstrated approach can be used for analysis of the influence of a high-voltage line on any elongated conductive object during transients. The proposed method is well suited for parallel computing due to linear nature of equation systems used.

This paper presents an adaptive transmission line fault location method, which incorporates fault location devices at both line ends and utilises data import from a supervisory control and data acquisition system without strictly requiring data synchronisation. The developed method aims at achieving a higher degree of robustness, adaptiveness and accuracy. The adaptiveness is achieved by dynamic updating of mathematical models used on the basis of network-wide information, such as data on the state of circuit-breakers and apparent power at load and generation nodes. The robustness and accuracy are enhanced by incorporating two stages of identification of model parameters with the goal of reducing the decision variable space for the stage identifying fault parameters. Furthermore, in addition to utilisation of all measurements available at a particular substation, the developed method partially employs the measurements from the other end of the line by means of result cross-checks, but does not require a full data set, unlike deterministic-model-based methods. An optimisation-based approach, redundancy on the basis of extended measurement set, and cross-checks reduce the risk of fault location errors due to measurement errors or “voids” in the data available. Testing of the developed method demonstrates its accuracy and robustness in a wide range